Originally published on
by at Arctic News
Antarctic sea ice extent on February 20, 2022, was only 1.983 million km². On February 20, 2008, it was 3.783 million km². That’s a difference of 1.8 million km², or some 0.36% of the total surface of Earth (which is 510,072,000 km²).
Albedo refers to the reflectivity of the surface. Earth average albedo is 0.3 or 30%. The albedo of sea ice can be as high as 0.9 (i.e. 90% when covered with fresh snow). Currently, albedo of the sea ice is about 0.6 (the sea ice is partly covered with melt pools). Open water has an albedo of 0.1. So, disappearance of the sea ice makes an albedo difference of about 0.5.
That’s almost half as much as all human-caused global warming in 2019 (radiative forcing was 2.72 W/m² in 2019 relative to 1750, according to IPCC AR6).
If anyone can add to or improve the above calculation, please add a comment (see box below).
The situation is dire and calls for the most comprehensive and effective action, as described at the Climate Plan.
• NSIDC – Charctic interactive Sea Ice Graph
• Wikipedia – Earth
• IPCC – Figure 2.11 (AR5/WG1/Chapter 2)
• The global energy balance from a surface perspective – by Martin Wild et al. (2012)
• Climate Plan